This invention relates to a laser apparatus including a main optical shutter adapted to attenuate or intercept a laser beam emitted from a laser beam radiation source and, more particularly, to a fail-safe laser apparatus including a safety optical shutter in addition to the main optical shutter to completely intercept the laser beam incident thereon in the event of failure of the main optical shutter.
Continuous radiation type laser beam radiation sources have been employed in machine tools, medical machines such as laser scalpels and laser coagulators, and length measuring machines. It is normal practice to provide a mechanical shutter movable between open and closed positions for interrupting the laser beam from a laser beam radiation source. In the event of failure of the mechanical shutter, however, the laser beam is emitted at an unexpected time, putting a person in danger. This is serious particularly for medical machines.